//
// Copyright (c) ZeroC, Inc. All rights reserved.
//

import { ConnectFailedException, ConnectionLostException, SocketException } from "./LocalExceptions.js";
import { WSConnectionInfo, TCPConnectionInfo } from "./Connection.js";
import { ConnectionInfo as SSLConnectionInfo } from "./SSL/ConnectionInfo.js";
import { SocketOperation } from "./SocketOperation.js";
import { Timer } from "./Timer.js";
import { Debug } from "./Debug.js";

export let WSTransceiver = {};

if (typeof WebSocket !== "undefined") {
    //
    // With Chrome we don't want to close the socket while connection is in progress,
    // see comments on close implementation below.
    //
    // We need to check for Edge browser as it might include Chrome in its user agent.
    //
    const IsChrome = navigator.userAgent.indexOf("Edge/") === -1 && navigator.userAgent.indexOf("Chrome/") !== -1;
    const IsSafari = /^((?!chrome).)*safari/i.test(navigator.userAgent);

    const StateNeedConnect = 0;
    const StateConnectPending = 1;
    const StateConnected = 2;
    const StateClosePending = 3;
    const StateClosed = 4;

    WSTransceiver = class {
        constructor(instance) {
            this._readBuffers = [];
            this._readPosition = 0;
            this._maxSendPacketSize = instance.properties().getPropertyAsIntWithDefault("Ice.TCP.SndSize", 512 * 1024);
            this._writeReadyTimeout = 0;
        }

        writeReadyTimeout() {
            const t = Math.round(this._writeReadyTimeout);
            this._writeReadyTimeout += this._writeReadyTimeout >= 5 ? 5 : 0.2;
            return Math.min(t, 25);
        }

        setCallbacks(connectedCallback, bytesAvailableCallback, bytesWrittenCallback) {
            this._connectedCallback = connectedCallback;
            this._bytesAvailableCallback = bytesAvailableCallback;
            this._bytesWrittenCallback = bytesWrittenCallback;
        }

        //
        // Returns SocketOperation.None when initialization is complete.
        //
        initialize(readBuffer, writeBuffer) {
            try {
                if (this._exception) {
                    throw this._exception;
                }

                if (this._state === StateNeedConnect) {
                    this._state = StateConnectPending;
                    this._fd = new WebSocket(this._url, "ice.zeroc.com");
                    this._fd.binaryType = "arraybuffer";
                    this._fd.onopen = e => this.socketConnected(e);
                    this._fd.onmessage = e => this.socketBytesAvailable(e.data);
                    this._fd.onclose = e => this.socketClosed(e);
                    return SocketOperation.Connect; // Waiting for connect to complete.
                } else if (this._state === StateConnectPending) {
                    //
                    // Socket is connected.
                    //
                    this._desc = fdToString(this._addr);
                    this._state = StateConnected;
                }
            } catch (err) {
                if (!this._exception) {
                    this._exception = translateError(this._state, err);
                }
                throw this._exception;
            }

            Debug.assert(this._state === StateConnected);
            return SocketOperation.None;
        }

        register() {
            //
            // Register the socket data listener.
            //
            this._registered = true;
            if (this._hasBytesAvailable || this._exception) {
                this._hasBytesAvailable = false;
                Timer.setTimeout(() => this._bytesAvailableCallback(), 0);
            }
        }

        unregister() {
            //
            // Unregister the socket data listener.
            //
            this._registered = false;
        }

        close() {
            if (this._fd === null) {
                Debug.assert(this._exception); // Websocket creation failed.
                return;
            }

            //
            // With Chrome (in particular on macOS) calling close() while the websocket isn't
            // connected yet doesn't abort the connection attempt, and might result in the
            // connection being reused by a different web socket.
            //
            // To workaround this problem, we always wait for the socket to be connected or
            // closed before closing the socket.
            //
            // NOTE: when this workaround is no longer necessary, don't forget removing the
            // StateClosePending state.
            //
            if ((IsChrome || IsSafari) && this._fd.readyState === WebSocket.CONNECTING) {
                this._state = StateClosePending;
                return;
            }

            Debug.assert(this._fd !== null);
            try {
                this._state = StateClosed;
                this._fd.close();
            } catch (ex) {
                throw translateError(this._state, ex);
            } finally {
                this._fd = null;
            }
        }

        //
        // Returns true if all of the data was flushed to the kernel buffer.
        //
        write(byteBuffer) {
            if (this._exception) {
                throw this._exception;
            } else if (byteBuffer.remaining === 0) {
                return true;
            }
            Debug.assert(this._fd);

            const cb = () => {
                if (this._fd) {
                    const packetSize =
                        this._maxSendPacketSize > 0 && byteBuffer.remaining > this._maxSendPacketSize
                            ? this._maxSendPacketSize
                            : byteBuffer.remaining;
                    if (this._fd.bufferedAmount + packetSize <= this._maxSendPacketSize) {
                        this._bytesWrittenCallback(0, 0);
                    } else {
                        Timer.setTimeout(cb, this.writeReadyTimeout());
                    }
                }
            };

            while (true) {
                const packetSize =
                    this._maxSendPacketSize > 0 && byteBuffer.remaining > this._maxSendPacketSize
                        ? this._maxSendPacketSize
                        : byteBuffer.remaining;
                if (byteBuffer.remaining === 0) {
                    break;
                }
                Debug.assert(packetSize > 0);
                if (this._fd.bufferedAmount + packetSize > this._maxSendPacketSize) {
                    Timer.setTimeout(cb, this.writeReadyTimeout());
                    return false;
                }
                this._writeReadyTimeout = 0;
                const slice = byteBuffer.b.slice(byteBuffer.position, byteBuffer.position + packetSize);
                this._fd.send(slice);
                byteBuffer.position += packetSize;

                //
                // TODO: WORKAROUND for Safari issue. The websocket accepts all the
                // data (bufferedAmount is always 0). We relinquish the control here
                // to ensure timeouts work properly.
                //
                if (IsSafari && byteBuffer.remaining > 0) {
                    Timer.setTimeout(cb, this.writeReadyTimeout());
                    return false;
                }
            }
            return true;
        }

        read(byteBuffer, moreData) {
            if (this._exception) {
                throw this._exception;
            }

            moreData.value = false;

            if (this._readBuffers.length === 0) {
                return false; // No data available.
            }

            let avail = this._readBuffers[0].byteLength - this._readPosition;
            Debug.assert(avail > 0);

            while (byteBuffer.remaining > 0) {
                if (avail > byteBuffer.remaining) {
                    avail = byteBuffer.remaining;
                }

                new Uint8Array(byteBuffer.b).set(
                    new Uint8Array(this._readBuffers[0], this._readPosition, avail),
                    byteBuffer.position,
                );

                byteBuffer.position += avail;
                this._readPosition += avail;
                if (this._readPosition === this._readBuffers[0].byteLength) {
                    //
                    // We've exhausted the current read buffer.
                    //
                    this._readPosition = 0;
                    this._readBuffers.shift();
                    if (this._readBuffers.length === 0) {
                        break; // No more data - we're done.
                    } else {
                        avail = this._readBuffers[0].byteLength;
                    }
                }
            }

            moreData.value = this._readBuffers.length > 0;

            return byteBuffer.remaining === 0;
        }

        type() {
            return this._secure ? "wss" : "ws";
        }

        getInfo() {
            Debug.assert(this._fd !== null);
            const info = new WSConnectionInfo();
            const tcpInfo = new TCPConnectionInfo();
            tcpInfo.localAddress = "";
            tcpInfo.localPort = -1;
            tcpInfo.remoteAddress = this._addr.host;
            tcpInfo.remotePort = this._addr.port;
            info.underlying = this._secure
                ? new SSLConnectionInfo(tcpInfo, tcpInfo.timeout, tcpInfo.compress)
                : tcpInfo;
            tcpInfo.rcvSize = -1;
            tcpInfo.sndSize = this._maxSendPacketSize;
            info.headers = {};
            return info;
        }

        setBufferSize(rcvSize, sndSize) {
            this._maxSendPacketSize = sndSize;
        }

        toString() {
            return this._desc;
        }

        socketConnected(e) {
            if (this._state == StateClosePending) {
                this.close();
                return;
            }

            Debug.assert(this._connectedCallback !== null);
            this._connectedCallback();
        }

        socketBytesAvailable(buf) {
            Debug.assert(this._bytesAvailableCallback !== null);
            if (buf.byteLength > 0) {
                this._readBuffers.push(buf);
                if (this._registered) {
                    this._bytesAvailableCallback();
                } else if (!this._hasBytesAvailable) {
                    this._hasBytesAvailable = true;
                }
            }
        }

        socketClosed(err) {
            if (this._state == StateClosePending) {
                this.close();
                return;
            }

            this._exception = translateError(this._state, err);
            if (this._state < StateConnected) {
                this._connectedCallback();
            } else if (this._registered) {
                this._bytesAvailableCallback();
            }
        }

        static createOutgoing(instance, secure, addr, resource) {
            const transceiver = new WSTransceiver(instance);
            let url = secure ? "wss" : "ws";
            url += "://" + addr.host;
            if (addr.port !== 80) {
                url += ":" + addr.port;
            }
            url += resource ? resource : "/";
            transceiver._url = url;
            transceiver._fd = null;
            transceiver._addr = addr;
            transceiver._desc = "local address = <not available>\nremote address = " + addr.host + ":" + addr.port;
            transceiver._state = StateNeedConnect;
            transceiver._secure = secure;
            transceiver._exception = null;
            return transceiver;
        }
    };

    function fdToString(address) {
        return "local address = <not available>\nremote address = " + address.host + ":" + address.port;
    }

    function translateError(state, err) {
        if (state < StateConnected) {
            return new ConnectFailedException("connect failed", { cause: err });
        } else {
            if (err.code === 1000 || err.code === 1006) {
                // CLOSE_NORMAL | CLOSE_ABNORMAL
                return new ConnectionLostException();
            }
            return new SocketException("socket exception", { cause: err });
        }
    }
} else {
    WSTransceiver = class {};
}
